“The replacement of Pine Creek Bridge No. 11 featured a challenging site that required a high level of coordination and communication during both the design and construction phases. Buchart Horn developed a quality design and supported that with timely, responsive service to address unexpected field conditions during construction. This enabled our construction team to minimize delays and successfully deliver a new bridge that improves capacity and safety for the residents of Allegheny County.” – Michael Dillon, PE, MBA, Deputy Director Engineering and Construction, Allegheny County Department of Public Works
Replacement of Pine Creek Bridge No. 11 presented a number of challenges related to the structure and the adjacent site. The existing bridge was a single-lane, single-span, 58-foot thru-girder structure carrying East Pennview Street (Pine Creek Bridge No. 11) over Pine Creek in Shaler Township, Allegheny County. The existing curb-to-curb width was 14 feet. The roadway geometry is on a horizontal curve and tangent across the bridge, with a vertical curve and superelevation transition.
Key design issues included:
- Railroad coordination
- Utility considerations
- Maintenance of traffic
- Alignment improvements
- Environmental site assessment
The new bridge is a two-lane, prestressed concrete adjacent box beam superstructure with a single span of 68 feet, 6 inches. The curb-to-curb width is 34 feet and allows for a buffer zone for pedestrians. Coordination with Allegheny Valley Railroad was required during the design and construction of the project. The existing abutment was approximately 18 feet from the centerline of the at-grade railroad tracks, which prompted the use of tangent caissons as a cost-effective alternative for the abutment on the railroad side. Railroad flaggers were required daily during construction due to active railroad traffic. There were also numerous overhead and underground utilities in the project area that required close coordination during design and construction. Maintenance of traffic in and out of an adjacent McDonald’s was also an important consideration.